Overexpression of Pseudomonas putida-responsive miR393a-5p attunes morpho-physiological and biochemical parameters in Arabidopsis

A healthy root system not only supports the upright posture of the plants but also serves as the basis for typical plant growth and development. Plant roots exhibit high degree of plasticity and are capable of physiological and developmental adaptation to their ever-changing surroundings. Several biological, cellular and molecular processes are regulated by microRNAs (miRNAs) under normal as well as drought condition, which are associated with plant metabolism, growth, and development. For the evaluation of Pseudomonas putida RA-responsive miR393a-5p functions in the growth and development, we have generated and functionally characterised At-miR393a-5p in Arabidopsis thaliana homologous system. Our results indicated that At-miR393a-5p overexpressing Arabidopsis exhibited diverse plant growth and development attributes, such as increased shoot length, primary root length, biomass, number of lateral branches and number of siliques as compared to the Col-0 wild type plants. The overexpression of miR393a-5p negatively regulates mRNAs of AtTIR1 and AtAFB2 in T₃ homozygous Arabidopsis. Additionally, all the overexpressing lines have improved water status, cell membrane integrity, proline accumulation and super oxide dismutase activity under drought stress. Over all, the results of this study suggested that miR393a-5p would be a promising candidate for enhancing agricultural productivity.